Instrument for watchmakers&#39; use.



No. 792.867. PATENTED JUNE 18, 1905. G. M. THOMSBN.

INSTRUMENT FOR WATGHMAKERS USE.

APPLICATION FILED MAB. 1. 1905.

J invlzummil;nuzawlunliulama 3- W 2/ n1 i, v 6 (CZ C 1/ Z are; amseiz ATTORNEY Patented June 13, 1905.

PATENT OEErcE.

CHARLES MELANCHTON THOMSEN, OF MINNEAPOLIS, MINNESOTA.

INSTRUMENT FOR WATCHMAKERS USE.

SPECIFICATION forming part of Letters Patent No. 792,367, dated June 13, 1905.

Application filed March 1, 1905. Serial No. 247,970.

To ztZZ whom it may concern.-

Be it known that I, OHARLEs MELANCHTON THoMsEN, a citizen of the United States, and a resident of Minneapolis, in the county of Hennepin and State of Minnesota, have invented a new and Improved Instrument for WVatchmakers Use, of which the following is a full, clear, and exact description.

This invention relates to watch-repairing, and more particularly to means for holding without injury the split hub or collet-that is the center of a hair-spring for a watch, so as to permit the hole in the collet to be accurately reamed and the collet fitted upon the supporting-staff, whereon it is mounted for control of the balance-wheel of the watchmovement. As the diameter of the staffs employed for the purpose indicated vary somewhat in different watch-movements, the collet of a hair-spring that has never been used must usually be enlarged in the diameter of its central perforation, and ordinarily this is efiected by driving a tapered mandrel therein while the collet and spring are seated upon a flat plate, and in case the collet is spread too much the hole mustbe closed by compression of the collet, sometimes injuring the hairspring and causing it to work imperfectly.

The object of my invention is to provide a novel simple instrument in the form of speciallyconstructed tweezers, which may be very conveniently and effectively used for holding firmly the collet of a hair-spring, so that a reamer or broach may be inserted through the hole in the collet and rotated for an enlargement of the hole to a proper size for an exactengagement with the staff whereon the hair-spring is to be mounted.

The invention consists in the novel construction and combination of parts, as is hereinafter described, and defined in the claims.

Reference is to be had to the accompanying drawings, forming a part of this specification, in which similar characters of reference indicate corresponding parts in all the views.

Figure 1 is a plan view of the improved tweezers and of a hair-spring held thereon. Fig. 2 is a side view of the same seen in the direction of the arrow in Fig. 1, showing a reamer applied. Fig. 3 is an enlarged partlysectional plan view substantially on the line 3 3 in Fig. 4, and Fig. 4: is a longitudinal sectional side view substantially on the line 4L 4: in Fig. 3.

The improved tweezers consists, mainly, of two similar elongated members 5 5, formed of resilient metal, secured together at corresponding end portions, as indicated at a in Fig. 2. The end portion a of the joined members is formed with a lateral enlargement 5*, and from the enlargement said members are gradually widened to a point 5. Upon the members 5 5 between the points a and Z; a flattened clamping-ring 6 is loosely mounted, which when moved toward the widened portion 6 serves to clamp the free ends of the members 5 toward each other. From the point 6 toward and to the free ends of the tweezer members 5 said members are narrowed and thickened, afiording two similar clamp ing-jaws 5". Near the outer extremities of the jaws 5 a perforation 0 is formed in each jaw, these perforations, that are at the transverse center of said jaws, being opposite each other. The perforations c at their adjacent or inner edges may with advantage be slightly cupped or countersunk, and the opposed faces of the perforated jaws are normally separated by the resilience of the tweezer members 5 5.

To afford clearance for a hair-spring coil, such as A, the jaws 5 are cut away on their adjacent faces, producing a shallow elongated recess (Z in each jaw, which recesses are opposite each other.

In Figs. 3 aud t, B represents a collet which is centrally aflixed within the hair-spring coil A by an attachment of the inner endv of the spring thereto, as usual, and it will be seen that the ring-like collet is slotted at a, conferring slight resilience thereto. Ordinarily the peripheral edges of the collet B at each side of the spring A are cut away, so as to bevel them, these bevel edges f being adapted to seat neatly in the countersunk edges of the opposite perforations c. A check-pin g is affixed in one jaw 5 near the perforation 0 and projects somewhat beyond the inner surface of said jaw. In using the improved tweezers a hair-spring. to be fitted, is gripped with a suitable implement and introduced between the jaws 5", and the collet B is exactly seated on the countersunk edge of one perforation 0. The jaws 5 are now compressed, thus clamping the opposite countersunk edge of the perforation c in the other jaw upon the remaining beveled edge of the collet B, and the clamping-ring 6 is forced toward the twin jaws 5 which secures the collet between said jaws. In placing the collet B between the jaws 5 the check-pin g is entered within the slote in the collet and serves to prevent a turning movement of the hair-spring and collet when operated upon. The perforation in the collet B is now exposed through the perforations 0 in the jaws 5 and a breach or like reamer C is inserted through the collet and rotated with pressure thereon, which will cut away the wall of'the perforation in the collet and increase its diameter.

It is to be noted that the exact centering of the collet in the clamping jaws 5 and the spring coil between said jaws insures the proper enlargement of the perforation in the collet. As the hair-spring and its collet may be removed from the tweezers and replaced exactly as it had been clamped therein, it will be seen that the hole in the collet may be caused to receive the staff it is to be mounted upon and be exactly fitted by a repeated reaming of the hole, if this is necessary.

Injurious percussion in the enlargement of the perforation in the collet B is avoided by the use of the improved clamping device, and the operation, that may be quickly effected, enables the safe and exact fitting of the hairspring hub or collet upon the staff that supports it.

Having thus described my invention, I claim as new and desire to secure by Letters Patent- 1. A tweezers instrument comprising two similar elongated resilient members joined together at one end of each and normally diverging toward their opposite ends, a narrow and thickened jaw formed on the free end portion of each tweezers member, said jaws near their free ends each having a perforation therein, the adjacent defining edges of said perforations being countersunk for the reception of the beveled edges on the collet of a hair-spring, and a flattened clamping-ring mounted upon the tweezers members, and adapted to clamp them toward each other when said ring is moved toward the jaws.

- 2. A tweezers instrument comprising two similar elongated resilient members joined together at one end and normally diverging toward their opposite end, a narrowed and thickened jaw formed on the free end of each member, said jaws each having a perforation transversely therein, said opposite perforations having adjacent defining edges countersunk and adjacent faces of the jaws being recessed, a stop-pin projected from one of the jaws toward the other near the perforations therein, and a flattened clamping-ring mounted loosely on the tweezers members and adapted to clamp them toward each other when said ring is moved toward the jaws.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

CHARLES MELANCH'ION THOMSEN.

l/Vitnesses:

J. MCKENZIE, WM. M. YANACEK. 

